At study entry, participants will be randomly assigned to receive either the dengue virus vaccine or placebo. They will remain in the clinic for 30 minutes after receiving the injection for monitoring. Study visits will occur at Days 2, 4, 6, 8, 10, 12, 14, 16, 21, 28, 56, and 180. All study visits will include a blood collection, and most study visits will include a physical examination. Female participants will have a pregnancy test at select visits. Participants will record their temperature at least 3 times a day for the first 16 days; study researchers will review these readings during the study visits.